Spark-plug.



fracasar-irrita tr/1D JD tatamio Specification of Letters Patent.

Patented May 8, 19317.

Application filed 311127 21, 1914. Serial No. 352,221.

To all whom 'it may concern.'

Be it known that lf, Osma C. Minnen, a citizen of the llnited States, residing at Roxborough, Philadelphia, in the county oi' Philadelphia and State ot Pennsylvania7 have invented new and useful lmprovements in Spark-Plugs, of which the follow- ,ing is a specification.

This invention relates t-o improvements in spark plugs for internal combustion engines and the like.

ln carrying out the present invention, it is my purpose to improve and simplify the general construction of spark plugs and to provide a plug wherein one electrode may be adjusted relatively to the otherso as to vary the length of the spark gap.

lWith the above and other objects in view, the invention consists in the construction, combination and arrangement of parts hereinafter set tort-h in and falling within the scope ot the claim.

ln the accompanying drawing;

Figure 1 is a view in side elevation ot a spark plug constrcted in accordance with the present invention.

Fig. 2 is a longitudinal sectional view therethrough.

Fig. 3 is a cross sectional view on the line 3MB ot Figi 2.

Fig. 4 is a similar view on the line l-t of Fig. 2.

Fig. 5 is a bottom plan view.

Fig. 5a is a cross sectional view through a modiied form of electrode.

Referring now to the drawing in detail, 1 designates a metallic shell forming 'the ground electrode of Vthe plug and having` one end threaded exteriorly as at 2 to engage the opening in the cylinder all and the opposite end threaded exteriorly as at 3. The outer surface ot the central portion ot the shell or casing` 1 is preterahly polygonal in cross section so as to receive a wrench or similar tool whereby the plug may he screwed into the opening in 'the cylinder. The interior ot the shell 1 at vthe cylinder end thereof is formed with a small here l and the remaining end portion ot' the shell forms a relatively large oore 5 and at the junction ot the hores -t and 5 is a shoulder 6 against which seats a packing ring 7. 8 designates an electrode holder Yformed oit porcelain or similar insulating material and disposed within the shell l. @ne end portion of the electrode holder 8 is relatively small in diameter as compared with the remaining portion thereot1 and such small portion tits within the small bore e ot the shell, while the large diameter of the holder tits within the bore 5 ot' the shell and at the junction ot the small and large portions ot the electrode holder is a shoulder 9 resting against the packing ring 7 and serving to hold the electrode holder within the shell in proper position. Formed in the holder 8 centrally thereof is a longitudinal hore 10, while formed on the outer' end of the electrode holder. that is the end remote from the c vlinder wall, is an outwardly projecting nipple 11 coaxial`with the bore 10 and terminating short otl the adjacent extremity of the casing or shell 1. 12 designates a circu lar block disposed within the outer end of the shell 1 and having a recess formed in `the inner tace thereof receiving the nipple 11 on the adjacent end of the holder 8 and formed integral with the block 12 and projecting outwardly therefrom is a boss 13 termed with a longitudinal bore 14 alining axially with the hore in the electrode holder S. rlhreaded onto the outer end of the shell 1 is an annulus 15 formed with an inwardly extending flange 1G engaging the shoulder formed at the juncture oto the hlock 1Q with the boss 13, such flange coacting with the shoulder 7 to hold the electrode holder 8 within the shell and prevent accidental movement thereof. rlhe outer surface otl the annulus 16 is preferably polygonal in cross section so that the annulus may he threaded onto the adjacent end ot the shell by means ot a wrench or similar tool. One end portion ot the hore 10 in the electrode holder S is non-circular in cross section and disposed within such non-circular portion and ot a cross sectional configuration corresponding thereto is a nut 17. Passed through the axially alining hores 10 and 1li and thrcadedly engaging the nut 17 is a stem 18 forming the power electrode ot' the plug and having the lower end thereof hevond the cylinder' extremity ot the shell equipped with an annular disk 19 and the opposit-e end screw threaded and projecting beyond the boss 14. The disk 19 is ot a diameter approximately equal to the interior diameter ot the shell at the cylinder end ot the latter and is spaced apart 'from the end of the shell to ornLthe spark gap.

imi

By means of this construction,l it willl he seen that the disk acts as a deieetor to break the passage oit the products ot combustion .into

l the shell of the plug when the gaseous min'.-

ture is exploded, thereby prolonging the lite of the plug and preventing mutilation ot Vthe inner end ot' the electrode holder 5 in the use of the plug. Threaded onto the lastmentioned end oit the stein lSis a loeli nut 2O and interposed between the Confronting surfaces et the leek nut 2O and the hess it are washer.' 2l, while disposed hetween the washers 2l is a bindingA spring 22 acting to hold the loch nut against accidental turningv move lent on the stein. Vv'hen it is desired to vary the distance between the dish l5) and the adjacent end of the shell l or power eleetrode so that the length et the spark gap nay he Changed, the nut 20 is loosened and "ie stein 18 rotated within the nut 17. ln Tie rotation of the stem the latter moves ngitudinall)T incident to the threaded connection between the same and the nat 1T and when the desired adjustment has been e' E.. `ained the lock nut 2O is tightened so as to old the power eleetrode against movement. It desired, the periphery of the disk 19 may oe serrated as shown in Fig. 5a so as to insure the segregating of the sparks jumping across the gap.

will seen that l have previded. a spark plug` wherein the power electrode may he adjusted relatively to the ground elee- 'i de o to vari.Y the length ot the sparky 1 i le y,... su a) and vneein the component pints are se eerreated and arraned as to reduce the possibilityv of derangenient to a. i'niniinuin. and enahle the spark plug le he readilyv seinhled and dismantled.

i elann:

ljiination a inetallir shell, having); a transl verse inner annular shoulder. a packing engaging' said shoulder, an electrode holder disposed in said shell and having a shoulder seated on said paehine', and formed with an nnthreaded polygonal horl and with an elongated unthreade l opening oiA lesser diameter than said boss, a eirenlar hloeh 'formed terininallv7 ot said shell, a hosts formed with a eavitiv in which said liloellits, said here havingits lower portion Aformed ot a unilorin diameter with said electrode holde and its upper portion reduced to lorni a shoulder7 a mp thi' aded on said shell and pressing the shoulder ot' said hess to hold the liess and holder in engagement. a stein screw threaded throughout its main length and adapted to pass loosely through the bore and opening ot' said eleetrode holder hut threaded into said boss. an annular dish 'loi-ined at one end oi" said stein, a nut litted simply in said polygonal bore, said stein being thrrarded into said nat, and a loel nut engaging the tree end of said sten'i7 said disk disposed outside of said shell. :n testimony wher' presence of t 

